Oregon quarterback Justin Herbert scrabbles for a first down against Michigan State linebacker Joe Bachie during the first half of the Redbox Bowl, Monday, Dec. 31, 2018, in Santa Clara, Calif. Tony Avelar, AP

Oregon wide receiver Dillon Mitchell watches the ball bounce off his hands for an incomplete pass against Michigan State during the first half of the Redbox Bowl on Monday, Dec. 31, 2018, in Santa Clara, Calif. Thearon W. Henderson, Getty Images

Michigan State quarterback Brian Lewerke gets his pass off under pressure from Oregon's Jalen Jelks during the first half of the Redbox Bowl on Monday, Dec. 31, 2018, in Santa Clara, Calif. Thearon W. Henderson, Getty Images

The junior defensive end’s left leg slid while trying to pressure Ducks QB Justin Herbert with about 5 minutes to play in the quarter. Willekes, an All-American and the Big Ten’s top defensive lineman, laid on the ground in Oregon’s end zone as MSU’s training staff rushed to his aid.

Trainers looked at Willekes’ left ankle, and he needed assistance to get off the field while not putting any pressure on his leg. Willekes eventually had to be carted back to the Spartans’ locker room.

Willekes returned to MSU's sideline in the fourth quarter in street clothes and on crutches, with his left foot in a hard walking boot.

He has yet to announce whether he will return to MSU for his senior season or enter the NFL draft.